"Joe Gwinn" wrote in message
...

The consensus answer is 79.7 degrees included angle; one assumes that
the target was 80 degrees. One would assume that people don't sweat
getting Vee-groove angles exact on steady rests.


79.7 degrees internal will likely flex enough to comform perfectly with an
80 degrees external once all is torqued down.

At 80.3 degrees, it would never conform regardless of how hard you tighten
things.

This measurement is likely accurate enough to exclude the 75 degrees of
Harrison lathes.

By the way, after I cleaned and inspected everything, I think I misread
the hand-stamped number. I had read it as 68, but I now think it's
actually 89, as in 1989.